Harnessing the Synergistic Effect of Acidic and Basic Sites in Nitrogen-Enriched α-TiP for Co-Catalyst-Free Selective...

Area of Science:

• Catalysis
• Materials Science
• Green Chemistry

Background:

• Developing environmentally benign catalysts for CO2 valorization is critical for sustainable chemistry.
• Traditional methods often require harsh conditions or cocatalysts, limiting their applicability.

Purpose of the Study:

• To synthesize and characterize a novel nitrogen-enriched, acid-base bifunctional titanium phosphate catalyst (CC-3A-TiP).
• To evaluate the catalyst's efficiency in the cycloaddition of CO2 and epoxides to cyclic carbonates under solvent-free conditions.
• To investigate the mechanism and energetic feasibility of the cocatalyst-free reaction.

Main Methods:

• Synthesis of CC-3A-TiP via intercalation of α-TiP with aminosilanes and cyanuric chloride.
• Comprehensive structural and spectroscopic characterization (e.g., confirming Lewis acidic and basic sites).
• Catalytic performance testing under mild, solvent-free conditions; DFT and kinetic studies to determine activation energy.

Main Results:

• CC-3A-TiP exhibits dual Lewis acidic (Ti4+, -OH) and basic (-NH-, -C=N-) active sites.
• Achieved >99% conversion, 99% yield, and 100% selectivity for cyclic carbonates without cocatalysts.
• Demonstrated excellent stability and recyclability (∼92% yield over five cycles).
• DFT and experimental kinetics showed significantly lowered activation energy (7.21 and 9.06 kcal mol-1, respectively).

Conclusions:

• The intrinsic bifunctional nature of CC-3A-TiP enables efficient, cocatalyst-free CO2 cycloaddition with epoxides.
• The catalyst offers a sustainable and highly effective route for cyclic carbonate synthesis.
• CC-3A-TiP holds significant promise for industrial applications in CO2 valorization.